This blog discusses current weather, weather prediction, climate issues, and other topics

Monday, January 16, 2012

Wednesday Snow Storm

I just looked at the latest model runs and it seems clear that we are going to have a major (but not a record) snowstorm, one that is NOT followed by major warming and heavy rain. No Slushmageddon, just Snowmageddon. Near all modeling systems are taking the low south of us--thus the uncertainty is considerably less than a day or two ago. (But to be fair, there is a chance that the solutions we have are wrong!) With the low going south, the cold air can stay in place...in fact, the cold air will be reinforced with flow moving southward out of British Columbia. But a southward trajectory also lessens the precipitation amounts in the central and northern portions of the state...so NW WA may get very little.Since the forecast is so critically dependent on the exact position of the low, we need to watch that today. There is still a chance this could end up as a wet event....snow turning to rain, particularly over the southwestern portion of WA.

And there is something else...ANOTHER pulse of snow will occur on Thursday.

Cutting to the chase, Seattle may well get 6+ inches of snow during the next two days. SW Washington could get more. The mountains, particularly the central Cascades southward could get feet--like 3-4 feet. In short, one of the biggest events we have had in years.

This has been a hard forecast for the models because there are two airstreams battling it out...one from the north and one from the south. Small displacements of the low (order of a few hundred miles) makes all the difference. Consider that the system has developed and moved over thousands of miles...this is not an easy thing to do.

There has been some hype about this event...it is NOT going to be as bad as December 1996. I remember that well. We had two snowstorm the last week in December and I had 21.5 inches on the ground at my house. Then it got very warm and windy and heavy rain rapidly melted the snow. Just a disaster, with collapsed roofs and slope failures.

Heavy snow followed by warm rain collapsed Edmonds boat shelters

You want to see some weather maps! You bet.

Tonight and tomorrow a weak disturbance is moving through with lots of snow showers. (see radar image below). Substantial snow shadowing in the lee (west) of the Olympics. Some folks out of the shadow will get a few (2-4) inches. Child's play compared to what will happen on Wednesday morning.

On Wednesday AM a low center, with an associated warm front will approach our region, and by 10 AM (42h forecast chart below) will be reaching the coast, while cool air remains in place over most of western WA. Another weaker low will follow on Thursday AM. Two snow events. Clearly, we are just on the edge of the interface between the cool and warm air, which makes the forecast much harder.

Here are the predicted snowfall maps for 24h ending 4 PM Tuesday (first one) and 4 PM Wednesday (second one). During the next 24h, there will be light snow over the western lowlands (less in the central Sound) and lots of snow in the mountains. For the subsequent 24 h, there are huge amounts in the Oregon and southern Washington Cascades and heavy amounts (8-12 inches) over the western lowlands. Eastern Washington and Oregon also get hit hard.

Bellingham gets cheated! And did I mention strong winds coming out of the Fraser River Valley and hitting NW Washington? Here is what is forecast for 1 PM on Wednesday:

Sometimes so much happens at once that is hard to keep up with it...Wednesday will be like that. This event will do wonders for the NW snowpack...particularly in Oregon where they have really been hurting. And we haven't talked about the extraordinary precipitation totals to the south of us, where some places will be getting 10-20 inches of rain (or its equivalent in snow) (see graphic):

As shown by this water vapor chart....this is the result of the famed pineapple express, with moisture streaming out of the tropics and subtropics towards the West Coast.

I am exhausted thinking about all this weather action. Anyway, lets watch this carefully tomorrow....looks solid...but no forecast is certain and if this prediction goes south, it won't be the first time. The southern part of the Washington could see snow turning to rain. Keep in mind EVERYTHNG is dependent on the location of the low pressure...if it moves farther north than our models suggest we could see much more rain in the mix.

PS: No luck finding my lost dog Leah tonight...but she appears to be running around in the area around 220th and 64th Ave W in Mountlake Terrace, near the Moose Casino. Let me know if you see her...info on the right...thanks...

58 comments:

well i guess living here in chehalis is going to a real treat and i guess i need to get kitty litter, cat food and kerosene. If there is no school then I can pull out all the math and reading/spelling, so its not going to be such a vacation for my 10 yo after all!

Our family is going on a cruise from Miami later this week. We had originally planned to fly out of SEA Wednesday night...but now we've bumped the flight up to tomorrow night. The extra cost with airfare and hotel is steep, but we figure it's better than missing the cruise because of a delayed/canceled flight on Wednesday.

Well, drat. Sounds like we in north Whatcom County will suffer our usual cold northeaster with none of the added fun (snow!). Although I wouldn't bet a dime on any predictions ~ and yes, that includes Cliff's blog. I put the most stock in his analyses, but nine times out of time they don't apply to/aren't accurate for us.

WOW! I'm so excited! I think I've walked about 20 miles the past two days around Beacon Hill, Georgetown and West Seattle. I really love the snow and I have a lot of free time, so this is absolutely perfect. Although this 35 degree rain is definitely a bummer.

Very minor request - could you move the timestamp to the top of the post. A lot of what you post is obviously time sensitive and it's helpful to know when the post was made without having to scroll to the bottom and then back up.

I can feel the excitement in your writing... I'm sure this type of event is what you live for. The forecast has been morphing over the past 96 hours and I would think it great that when the event is over you could go back and give a play-by-play account of what has gone on. You could point out the pinnacle point that cause things to slow down, or speed up, why it went further south...Hope you get some sleep tonight, because tomorrow sounds like a meteorologist Christmas eve. I know I have felt some anticipation....

I want to get excited for this but our temperature here in Eatonville has gone from 32 earlier this evening and it is now hovering between 33/34. What's up with that? Is cold air going to filter down tonight? My kids sure hope so! I think we are the only district in the state that isn't calling a late start! Thanks for the updates Cliff! And good luck finding your dog!

Any chance of the models trending north so the north sound gets snow?The NWS showed me getting almost 15 inches over the next few days and now I will be lucky to get an inch or two?I hope the forecast shifts a little, but great blog anyway Cliff.

I sure hope you are wrong on this one, Cliff. I'm wishing for an epic, ski-to-work, firehose of snow on Bellingham. C'mon, weather-loving 'Hamsters, let's psychically nudge that express a little to the north! But safely...

Wow... looks like Olympia is set to get two feet from the coming storms!

Relatively mild temperatures tonight here in West Seattle currently. Light precip has been mostly rain mixed at times with a little snow -- with the wind, there's lots of melting happening here tonight.

After taking a stroll to knock the snow off the heavily leaning black bamboo and the Monster Purple Broccoli I see that more snow in Bellingham might be simply redundant. I'll be ok if Seattle gets slammed, then turns to Slusmageddon while we in the North bask in winter wonderland a while longer... : )

I'm still having doubts. Are the temperatures going to stay cold or get colder before Wednesday? Right now at midnight in Spanaway it's 34 degrees, enough to snow, but not stick. It's the same with Redmond at 34 degrees and Everett at 35.

Generally it's been warming up about 5 degrees during the day time, so I'm not seeing how we are to expect a huge amount of snow unless there's another cold front coming in ahead of it. It looks to me like the current air isn't cold enough for snow that sticks.

Really? It's 12:29 am and here at 210' elevation in Bellevue, it's windy and snowing a little, but standing outside, I can hear the snow melting off the roof and our cars. My skepticism is growing... will we actually have enough snow to keep us from the office tomorrow?

As of 0335h PST (1135 GMT) temps have remained between 32.8 - 33.4 here in the hills of Bothell. Some light rain has passed through and caused some trees to either lose their snow or become overweighted and sagging. The temps have remained steady since 1830h PST (0230 GMT). I fear when the cold air hits, it will cause a frozen layer topped by copious amounts of snow that are looking more certain with each passing hour.

I share everyone's enthusiasm about the snowstorm...I can't wait! However, regarding what Cliff Mass said about what can happen to roofs due to a heavy snow followed by rain, I'm a little concerned about my workplace, which is the Fred Meyer in Greenwood. It has a flat roof, which leaks in several places in the store when there's a heavy rain. Oh well, I'll hope for the best. Oh, and I'll say a prayer or two that little Leah is found before the storm hits.

There's already a foot of snow covering the back yard this morning, just outside of Bellingham. (I haven't peeked out at the front yard, so that could be just an inch or two of snow, but I suspect it is similar to the back yard.) As such, while I would appreciate another foot of snow, and the opportunity to miss a day of work, I can tolerate missing out on some snow. We're not getting cheated -- we just got our fill already, and now it's Seattle's turn.

Im starting to think this major snow storm will be a MAJOR BUST. Northgate snow been melting and temp holding steady at 33 all night long with a breezy south winds and snow mixed with rain off and on. My guess this storm tomarrow will be nothing but a warm rain and maybe a little wind.

It was raining this morning in Redmond, most of the main roads are wet but clear.

And I remember the snow storm of 96 as well. Had to drive all the way from Salem OR to Seattle area. In a sports car with stock tires. Ouch! Made it all the way up without "incident" and then got stuck in the parking lot of my Apt. LOL

Still no snow on the ground in the Magnolia neighborhood of Seattle. It snowed for an hour Sunday @4:30, but other than that just nothing. My kids were able to sled that envening on about an inch of snow. Since then, no snow and temps in the upper 30s. And we now have bare grass and clear, wet streats. Anyone nostalgic for these conditions should head over to the 'hood.

Still no snow on the ground in the Magnolia neighborhood of Seattle. It snowed for an hour @4:30 Sunday but since then we've had temps in the upper 30s and no additional precip. My kids are taking the lack of snow personally. Good (???) thing is the late start for school today at the local neighborhood school due to the... snow???

Goodness gracious folks, get a grip! We had light precipitation falling as rain and wintry mix in some areas. There was heavy snow north and south. As soon as the precipitation got going again (exorcising that annoying snow hole) it's switched back over to some of the heavier snow I've seen since Saturday. The fact that the Winter Storm Warning went up at 5am means snow is still on deck.

The Convergence Zone has actually missed a lot of the action this time around with Sunday and Monday snow showers more miss than hit. Getting some this morning, but we're still on the edge. Looks like we'll be on the edge tomorrow too, but scratch out some decent totals.

The latest models still went with the southerly route. You can even jog the low a little further north and it'd only mean MORE snow for Seattle. It is possible the low could take a wild turn north of course, but that lessens the closer we get (think of hurricane paths and the cone of uncertainty).

Regarding your dog, if you haven't already get in touch with Missing Pet Partnership. They're a wonderful non-profit who can send a tracking dog out and help you with other areas of the search. They have a high success rate. They helped with the recovery of my dog who went missing for 10 days during the snow storm in November 2010.

Here on No. Capitol Hill the coldest temp so far this winter is 28.5 degrees. This is unusually mild in comparison to the last several winters and more like our winters of 10-20 years ago in my recollection. This year it reflects all the dry inversions as the result of stalled high pressure areas (somewhat atypical for a La Nina year). It looks like things are finally moving along. Also I seem to recall more hits than misses in snowfall forecasts over the years, with the error usually on the high side of actual amounts. Is the new radar setup for the coast helping any?

I'm with Bruce M. on this one. You hyped this event in two posts yesterday calling it the possibile biggest snowstorm in years. Granted you also warned that things can change but to go back now and change the post without noting that you changed the post after publishing because models changed smacks of revisionist history.

I know that the Times and the PI and likely countless others linked to that post (with good reason) and you want to be sure that people are getting good information, not hyped information, but you should note when you change a story simply by adding "edit:" or "Update:" in front of the added or changed text.

Cliff...when viewing your blog posts via RSS readers, it appears as though the date is off on the RSS reader. Not sure if that originates on your side or where, but it's a bit confusing. OR...perhaps I need some new glasses. Can you take a peek at your blog via an RSS reader to see if the dates and times are consistent with your posting times and dates? Thanks much!